Surface analysis of copper plates exposed to the ambient atmosphere at different distances from the Sea of Japan coastline by FT-IR reflection absorption spectroscopy

Abstract

Copper plates were exposed to the ambient atmosphere in locations at different distances from the Sea of Japan coastline in order to investigate metal corrosion characteristic of weathering in winter. The samples from along the Sea of Japan coastline at Akita, Kanazawa, and Tottori districts were compared with those of Naruto district. The samples were analyzed by FT-IR reflection absorption spectroscopy (RAS). The formation of sulfato complexes and hydroxy species as well as oxides of Cu₂O and CuO was observed on the samples in all regions, but the formation rate of their species was different. The formation rate of the species from samples along the Sea of Japan coastline rapidly proceeds while that of the samples in Naruto district proceeds slowly in the winter season. Polishing the surface of the copper plate with emery paper revealed that an oblique baseline observed in the IR-RAS spectrum of the corroded samples is attributable to roughness on the surface of the copper plates which is mainly caused by weathering.